Self-Healing Structures
Using Cell Induction
Selvin George
22-Apr-03
CS851: Bio-Inspired Computing
Mickey lived a carefree life…
22-Apr-03
CS851: Bio-Inspired Computing
Until one fateful day…
Oh Poor Mickey…
Write you a better
program I must!
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CS851: Bio-Inspired Computing
Understanding Nature’s
System Model
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Large number of un-reliable cells
No unique ID, global position etc.,
No global communication
Physics and Chemistry
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No gravity, simple chemical reactions
Single Program on each cell
…Swarm Programming
22-Apr-03
CS851: Bio-Inspired Computing
Understanding Nature’s
Cell Model
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Awareness of Environment
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Cell Actions
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Sense chemicals on cell walls
Cell Division
State Change
Emit chemicals to neighbors cell walls
Diffuse chemicals over a short range
Simple forces to model cell displacement
Chemicals can nullify each other

(A, 1) + (B, 0.5) -> (A, 0.5) + (salt, 0.5)
22-Apr-03
CS851: Bio-Inspired Computing
Devise a better
Programming Model
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A can induce B by
short range diffusion of
chemicals
A and C can induce B
by emitting chemicals
across their cell walls
Induced Cell can
perform actions
dependent upon the
direction of induction
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B
A
A
B
C
C
A
CS851: Bio-Inspired Computing
C
B
C
C
Example – Sphere Program
A
alive < 1
alive > 0
B
alive < 1
& A>1
22-Apr-03
state A {
emits (alive, 1) diffuses (A, 10)
transitions
(alive < 1) from any direction
-> (A, B) in same direction;
-> (A);
}
state B {
emits (alive, 1)
transitions
(alive < 1) from any direction & (A > 1)
-> (B, B) in same direction;
(alive > 0) from any direction -> (B);
-> (A);
}
CS851: Bio-Inspired Computing
Sphere Development - 1
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CS851: Bio-Inspired Computing
Sphere Development - 2
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CS851: Bio-Inspired Computing
Sphere Development - 3
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CS851: Bio-Inspired Computing
Sphere Development - 4
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CS851: Bio-Inspired Computing
Sphere : Damage (66%)
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CS851: Bio-Inspired Computing
Sphere Healing - 1
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CS851: Bio-Inspired Computing
Sphere Healing - 2
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CS851: Bio-Inspired Computing
Sphere Healing - 3
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CS851: Bio-Inspired Computing
Sphere Healing - 4
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CS851: Bio-Inspired Computing
Performance of Sphere Program
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CS851: Bio-Inspired Computing
Meanwhile …
Ahem!
How is my
program
going?
22-Apr-03
CS851: Bio-Inspired Computing
A Quick look
Mesh Program
state corner {
emits (A, 5), (alive, 1) in all directions
transitions
(alive < 1) from any direction
-> (corner, segment) in same direction;
-> (corner);
}
state segment {
emits (alive, 1) in all directions
transitions
(A > 0) from any direction
& (alive > 0) from opposite direction
-> (segment) emits (A - 1) in all directions;
(A > 0) from any direction
-> (segment, segment) in opposite direction
emits (A - 1) in opposite direction;
(A = 0) -> (corner);
}
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CS851: Bio-Inspired Computing
Mesh – Developed
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CS851: Bio-Inspired Computing
Mesh – Damaged
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CS851: Bio-Inspired Computing
Mesh – Healed
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CS851: Bio-Inspired Computing
The Mickey Skeleton
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CS851: Bio-Inspired Computing
Mickey : Development – 1
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CS851: Bio-Inspired Computing
Mickey : Development – 2
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CS851: Bio-Inspired Computing
Mickey : Development – 3
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CS851: Bio-Inspired Computing
Mickey : Development – 4
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CS851: Bio-Inspired Computing
Mickey : Injured
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CS851: Bio-Inspired Computing
Mickey : Healing – 1
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CS851: Bio-Inspired Computing
Mickey : Healing – 2
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CS851: Bio-Inspired Computing
Mickey : Healing – 3
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CS851: Bio-Inspired Computing
Mickey : Healing – 4
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CS851: Bio-Inspired Computing
Applications: Distributed Wireless File Service
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File Replication
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Node possessing file emits
inhibit (shorter-range) and
replicate
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Node receiving replicate but
not inhibit replicate the file
File Request/Response
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Node requests a file
Typically one server
responds.
22-Apr-03
CS851: Bio-Inspired Computing
Conclusions
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Nature’s programs can heal and regenerate
lost components
System designers can learn principles of
robustness from nature’s programs
Simplify the task of programming robust
systems
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Cell Based Programming
Cell Induction
22-Apr-03
CS851: Bio-Inspired Computing
All’s well that ends well
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CS851: Bio-Inspired Computing
Questions and Answers
22-Apr-03
CS851: Bio-Inspired Computing